When drilling for hydrocarbons, any of a variety of measurement and transmission techniques are used to provide or record downhole data. Measurements of surrounding subterranean formations may be obtained using downhole measurement and logging tools, such as measurement-while-drilling (MWD) and/or logging-while-drilling (LWD) tools, which help characterize the formations and aid in making operational decisions. Such wellbore logging tools make measurements used to determine the electrical resistivity (or its inverse, conductivity) of the surrounding subterranean formations being penetrated. The electrical resistivity is responsive to various geological features of the formations, and the resistivity measurements can be interpreted to obtain useful information about those formations.
Resistivity logging tools include one or more antennas to obtain formation resistivity values. Such tools often include multiple antenna assemblies (alternately referred to as subs) axially spaced from each other along the tool string. The antenna assemblies make absolute resistivity measurements of the surrounding formation, which are susceptible to amplitude and phase noise that is often unable to be corrected via proper calibration. Moreover, the antenna assemblies measure frequency responses sequentially, which can cause timing and spatial errors due to movement and rotation of the bottom hole assembly as it rotates during operation. As a result, conventional resistivity logging tools often require accurate synchronization between the transmitter antenna and the receiver antenna(s). In some cases, this can require low drift clocks to be deployed on each transmitter and receiver antenna, as well as signal telemetry between the transmitter and receiver antennas.